Machines which automatically peel stone fruit and in particular mangoes are known. An example of such a machine is described in Australian Patent No. 602073. This machine has a curved peeling blade, which conforms to the concave outer surface of the mango. The mango is first halved and seeded and then transported by conveyor belt towards the peeling blade. The mango is urged past the peeling blade by means of an overhead profiled belt. Slicing blades are associated with the curved blade to both slice the mango and to guide the mango half through the peeling blade. However, such an arrangement is unsuitable if it is desirable for the fruit to be peeled as a single piece rather than slices. For example, slices are typically unsuitable for further processing in dicing machines.
The distance through which the centerline of the fruit skin moves as it passes through the peeling blade is greater than the distance moved by the edges of the skin. However, the profiled belt and roller arrangement as described in AU602073 moves fastest at the edges of the skin and slowest at the centerline. In practice, this difference in travelling speeds causes uneven feeding of the fruit past the blade and/or jamming of the fruit in the machine. Another mmango peeling machine, described in Australian Patent No 621411, employs a similar curved peeling blade. However, a pair of counter rotating traction wheels are used to urge the mango past the blade. Each wheel has a rim profiled to conform to the shape of the peeling blade. The distance between the rim and the blade controls the peeling depth. The rims are adapted to grip the skin of a piece of mango, which is being fed by a conveyor toward the rotating wheels. When the mango reaches the wheels, it is gripped by the rims and urged downwards through the peeling blade. Use of the profiled rims enables the different speeds of the centerline and edges of the mango as it travels through the peeling blade to be accommodated.
The machines as described above are operated by electric motors which operate chain or belt drives. However, such drive systems are expensive to fabricate, install and align. Regular maintenance and servicing is also required. Further, after a period of time, the chain or belt and respective guides become worn and/or loose. In the case where the peeling machine has a pair of counter rotating wheels, the chain drive is subject to wearing and stretching. When such wearing and stretching occurs, the fruit may be gripped in an uneven manner by the wheel rims. This causes the fruit being to be fed to peeling blade in an uneven or skewed manner. This results in non-uniform peeling of the fruit.
Another disadvantage of the above machines, is that the size of the drive mechanisms require a relatively large housing. This means that the size of the machine prevents its application in the domestic kitchen or smaller spaces such as a restaurant or cafe. Another feature of the known machine which makes it unsuitable for these applications is that the drive mechanisms generate considerable noise.